But each blow sends powerful forces toward the soft tissues at the beak's base, and no one had ever managed to figure out how the beak dissipates those forces to prevent damage.

So Ali Miserez and his colleagues at the University of California, Santa Barbara, painstakingly sampled bits of beak all the way from tip to base and discovered changing ratios of chitin (a tough sugar chain), water, and proteins in a matrix that spans the length of the structure.

The beak exhibited an overall stiffness gradient that differs a hundredfold from beak tip to base. Though rigid at its cutting end, the beak gradually becomes softer and more flexible as it approached the soft muscle tissue.

The findings offer a potential solution for the longtime engineering struggle to attach mechanically mismatched materials.

"This could really revolutionize the way engineers think about attaching materials together in all sorts of applications," Frank Zok, a study co-author, said.